Science: Nobel Winners

Nobel prizes in physics and chemistry, worth $29,000 each, went last week to three men who have been studying atoms. Like the recent Nobel awards in medicine (TIME, Nov. 6), these were for two years, 1943 and 1944. The winners:

1943 Physics—Otto Stern, 56, a bald, stocky, mustached German, old friend & associate of Albert Einstein, who quit the University of Hamburg when the Nazis came to power, is now a U.S. citizen and research professor at Carnegie Tech.

1944 Physics—Isidor Isaac Rabi, 46, tousle-haired Columbia professor, born in Austria and raised in New York City, who is now on war leave at M.I.T.’s Radiation (electronics) Laboratory.

1943 Chemistry (the 1944 prize will be awarded later)—Georg von Hevesy, 59, Hungarian-born professor at Copenhagen’s Institute of Theoretical Physics, now a refugee in Stockholm.

Eight of the last ten Nobel physics awards have gone to atomic researchers. Stern’s and Rabi’s awards were for studies of the atom’s nucleus—the core of protons and neutrons.

Molecular Beam. Stern and Rabi tackled the question: what holds the nucleus of an atom together? Its protons have positive charges which repel each other, yet the nucleus as a whole possesses a magnetic force that keeps them from breaking loose. Nuclear magnets are so small that for a long time no one knew how to measure them. But at Hamburg, where Rabi worked with Stern as a graduate student, Stern discovered how.

He developed a “molecular beam” consisting of a stream of molecules shot through a very fine slit into a vacuum tube. In the empty tube, each molecule traveled in a straight line. When it was subjected to a magnetic field, a molecule’s magnetic “moment” or force could be gauged by the extent of its deflection from a straight course.

Rabi, carrying these studies further, found the molecular beam much more helpful in studying the structure of an atom than an atom-smashing machine, whose use he likens to studying the Taj Mahal by dynamiting it and considering the fragments. By his method, Rabi learned, for example, that the deuteron, the simplest known nucleus, revolves like a football spinning end over end.

Isotopes and Hafnium. The work of the chemistry prizewinner, Hevesy, was related to the physicists’ researches. He studied atoms by means of X rays and isotopes (slight variations in chemical elements which differ from each other only in radiactivity or atomic weight). By X-ray analysis, Hevesy discovered hafnium, No. 72 in the table of elements.

By bombarding molecules to make them give off distinctive rays, he traced chemical changes in the body with great exactness. He followed an individual molecule’s course through the body with a ray detector—something like watching the movements of a dyed member of a school of fish. One of his findings: a given water molecule, after drinking, usually stays in the human body about 13 days. For example, in urination, an individual expels not the liquid last drunk but the older accumulations in his body’s reservoir.